This invention relates generally to an air intake shutoff device and, more particularly, to an air intake shutoff device for an engine having multiple air shutoff valve assemblies.
Internal combustion engines may be operated in a variety of environments. Some environments associated with, for example, marine propulsion power, marine auxiliary power, petroleum production, locomotive applications, mining, industrial applications, electrical power generation, and chemical plants may include atmospheres with high levels of volatile hydrocarbons. In such applications, these volatile hydrocarbons may be drawn into air intakes of the engine and supplied to the engine cylinders. These hydrocarbons may act as a secondary fuel source and can combust along with the regularly supplied fuel. As a result, the engine may operate uncontrollably to a point where the engine rotates at a speed in excess of its design limits. Catastrophic engine failure may occur if the secondary fuel source is not eliminated.
To prevent catastrophic failure, internal combustion engines may include an air shutoff device that blocks all airflow to the engine. Such an air shutoff device may be configured to include multiple air shutoff valve assemblies, each having a gate that blocks the airflow into a respective air intake passage of the engine. These air intake passages may be associated with turbocharger units, for example. The air shutoff valve assemblies may be manually or automatically actuated using, for example, electrical or hydraulic actuators. In the event that unwanted, combustible hydrocarbons are drawn into an engine and an over-speed condition results, the air shutoff device may be activated to perform an emergency engine stop (i.e., an xe2x80x9ce-stopxe2x80x9d event) in which each air intake pathway into the engine is blocked by a respective air shutoff valve assembly. By shutting off the air supply to the engine, the shutoff device starves the engine of oxygen and the secondary fuel source and terminates combustion in the cylinders. In this manner, the air shutoff device may prevent damage to the engine caused by uncontrolled over-speed.
After an e-stop event, each air shutoff valve assembly of the air shutoff device must be reopened prior to re-starting the engine. Operation of the engine with only some of the air shutoff valve assemblies in the open position can result in engine damage. In existing air shutoff devices, the responsibility to ensure that all of the air shutoff valve assemblies of the air shutoff device were fully opened belonged to the engine operator. Because the air shutoff valve assemblies of existing air shutoff devices were not linked together mechanically, the engine operator had to manually open each air shutoff valve assembly after an e-stop event. This arrangement takes time and increases the likelihood of engine damage caused by an air shutoff valve assembly inadvertently left closed prior to re-starting the engine.
The present invention is directed to overcoming one or more of the problems or disadvantages existing in these former systems.
A first aspect of the invention includes an air intake shutoff device for an engine. The device includes at least two air shutoff valve assemblies. Each of these assemblies has a gate for controlling air flow into the engine. A linkage couples together the gates of each of the air shutoff valve assemblies such that closing of one gate of the at least two air shutoff valve assemblies effectuates closing of all other gates of the at least two air shutoff valve assemblies.
A second aspect of the invention includes a linkage for an air shutoff device of an engine. The linkage includes a shaft having a first end and a second end and defining a longitudinal axis. A first universal joint has a near end and a distal end and is attached to the shaft such that the near end of the first universal joint connects to the first end of the shaft. A second universal joint has a near end and a distal end and is attached to the shaft such that the near end of the second universal joint connects to the second end of the shaft.
A third aspect of the invention includes an engine having at least two turbochargers. An air shutoff valve assembly is attached to each of the at least two turbochargers, and each air shutoff valve assembly includes a gate for controlling the flow of air to the engine. A linkage couples together the gate of each air shutoff valve assembly such that closing of the gate of one air shutoff valve assembly effectuates closing of all other gates of the air shutoff valve assemblies.